This invention relates to braiding fibers into a preform shape, and more particularly, it relates to composite article of fiber reinforced resin matrix formed from a braided preform.
Fiber-reinforced plastic structures have been used for many years with increasing success because of their high strength, light weight and ease of fabrication compared to the wood or metal structures which they replace. Fibers such as glass, carbon and aramid are popular as reinforcement, and resins such as polyester, phenolic and epoxy are common polymeric matrices.
Polymeric materials reinforced with continuous filaments are used as precursors for highly-stressed parts such as aerospace components requiring high strength with low weight and which offer other advantageous properties such as thermal oxidative stability and lubricity.
It is known to adapt commercial braiding equipment to produce fiber reinforced resin components. Impregnation has been accomplished by using pre-impregnated fibers in the braiding operation or by continuously impregnating the fibers with resin during braiding as disclosed by Kruesi in U.S. Pat. No. 4,494,436. However, when preparing preform articles by braiding on a support mandrel, it is essential that the preform be self-supporting when removed from the mandrel yet having sufficient volatile content to minimize the loss of resin due to mechanical handling in further processing steps. The loss of resin occurs when the preform becomes too dry and the resin breaks or flakes off the preform when it is handled.
Even using state of the art technology to form the final composite part, the dimensional and performance requirements of aircraft and aerospace components and the need to provide high quality components at a low cost are difficult to achieve.